Digital imaging systems have now gained wide acceptance in the preparation of printing precursor elements for use in printing operations. For example, flexographic printing presses are widely used in the printing of packaging products where the use of a compressible relief imaging element is advantageous for printing on a variety of substrates including, for example, plastic and cardboard. A flexographic media generally comprises a layer of photopolymer that is exposed to UV radiation through an image mask, such as a film, to selectively harden the photopolymer.
In recent years digital flexographic media has become available with an integral image mask layer that is imaged in a digital imaging system using an imagewise-controllable laser source. The media is typically made available in flat plate sections that are adhered to a cylindrical flexographic printing form after the relief image has been formed and processed. Interest is growing in providing continuous flexographic elements that have no discernable seam joints around the periphery of the cylinder. Seamless flexographic printing elements are particularly useful in printing continuous repeat patterns such as wallpaper and wrapping paper.
The handling of both flat and seamless flexographic media presents a problem. Imaging devices, which use flat media have a cylindrical drum around which the flat media is wrapped. Imaging devices which use seamless media have a mandrel over which a sleeve can be loaded. Additionally flexographic printing forms are often used in VLF (Very Large Format) sizes such as the ThermoFlex™ 5280 sold by Creo Inc of Burnaby, British Columbia, Canada, which is able to load flat media sized up to 52 inch by 80 inches. The large size of VLF media along with the industry demand to handle seamless sleeve formats presents a challenge for media handling.
The problem is not confined to the flexographic printing field. The handling of multiple formats of imaging media in lithographic platemaking, gravure, proofing, and other imaging areas also has the same problem that different media require different apparatus for imaging. There remains a need for better methods and apparatus for accommodating a variety of different sizes and formats of media in imaging devices.